The present invention provides a new structure of a regenerative pump, fluid be circulated many times by vanes inside pump casing to get higher head. The new flow model of the flow channel is based on two streamlines of flow channels, one flow channel inside pump casing and one flow channel in vanes with closed impeller, those streamline have larger radius curvature to keep flow more smoothly. One of new features of new structure of pump is the maximum width nearby the leading edge of vanes of impeller, it could enlarge the radius of curvature of the streamline both at leading edge and trailing edge, and to reduce flow disturbance also; Closed type impeller is another feature, it could reduce flow disturbance between whirl area, the central part of flow model, and impeller, and separate the whirl area at side space of shroud plate of impeller, so vanes only works down the fluid inside the flow channel, and not works down the flow at the whirl area, and keep the whirl area in lower velocity to avoid tip vortex at shroud, and the whirl area is down size also; The trailing edge at outlet diameter of impeller is a incline line is another feature, the edge from out diameter of shroud extending slantingly to out diameter of hub plate where, so that the fluid could get larger curvature radius during outwards flowing from trailing edge by earlier turning. Separated whirl area by shroud plate to reduce disturbance between flow and impeller, so it could achieve the goal of reducing noise, increasing the outflow capacity and getting higher efficiency.